1. Field of the Invention
The present invention relates to a collapsible lens barrel and to an imaging apparatus.
2. Description of Related Art
A collapsible lens barrel, which incorporates an image-capturing optical system, which is adapted to collapse and/or expand in an axial direction along the optical axis thereof, and which is used as a lens barrel for an imaging apparatus, such as a digital still camera and a digital video camera, for example, is available.
Such a collapsible lens barrel has plural lens holding frames, which are disposed at places in front of an imaging device for electronically imaging an object, which optical image is formed by the image-capturing optical system, in such a way as to move along the direction of the optical axis thereof, and also has plural drive mechanisms for moving each of the lens holding frames in the direction of the optical axis thereof.
For the drive mechanisms, there have been proposed mechanisms, each having a male screw member extending in the direction of the optical axis, a motor for rotation-driving the male screw member, and a female screw member screwed in to the male screw member and moved in the extending direction of the male screw member and adapted so that this female member is connected to the lens holding frame, and the lens holding frame is moved, together with the female screw member, in the direction of the optical axis by rotation of the motor (see, for example, Japanese Patent Application Laid-Open No. 2002-286988 Official Gazette).
In such a collapsible lens barrel, each of the lens holding frames is moved to a rear end position, which is located at the rearmost place in the direction of the optical axis, in a collapsed condition. At that time, to prevent each of the lens holding frames and the drive mechanisms therefor from being damaged, clearances should be ensured between the lens holding frames and between the lens holding frame, which is positioned at the rearmost place, and a component provided at the rear end of the barrel.
On the other hand, there has been proposed a collapsible lens barrel in which an abutting member is provided at the frontmost position of the plural lens holding frames arranged in the direction of the optical axis in such a way as to be able to move in the direction of the optical axis, and in which a compression coil spring is disposed between the rear end of the abutting member and the adjacent lens holding frame (see, for example, Japanese Patent Application Laid-Open No. 2002-383449 Official Gazette).
Such a collapsible lens barrel is adapted so that in the collapsed condition, each of the lens holding frames is retreated through the compression coil spring by backwardly moving the abutting member, so that the plural lens holding frames are made to abut against each other, and so that the lens holding frame provided to the rearmost position is made to abut against the rear end of the lens barrel.